1. Using a Microscope

2. Parts of a
Microscope

4. As magnification increases, the field of view decreases!

5. At 40x magnification you will be able to see 5mm.
At 400x magnification you will be able to see 0.45mm, or 450 microns.
At 1000x magnification you will be able to see 0.180mm, or 180 microns.

6. 1X Low power – 10X

7. Medium power – 25X High power – 43X

8. Focusing Microscopes
Because specimens are three dimensional, and vary in thickness, you must make adjustments as you view the specimen. This is especially true if you are looking a live organisms that are moving.

9. Calculating Magnification
The magnification of an object is calculated by multiplying the magnification of the eyepiece lens (10X) by the magnification of the objective lens. Ex) 10X x 43X = 430X

11. 10X
20X
40X

12. Using A Microscope
Start on the low objective lens with the stage lowered and the specimen placed on the stage.
Adjust the course adjustment knob until you can see the image.
Use the fine adjustment knob to focus clearly on the specimen.
Rotate the nosepiece to high power. Do not move the stage!
Use only the fine adjustment knob to bring the specimen into focus!

13. Escherica coli (bacterium)
1000X um

14. Human Red Blood Cell
1000X um

15. Human Egg Cell
1000X 100 um

16. Saccharomyces cerevisiae (Yeast)
1000X um

17. Streptococcus pneumoniae (Bacterium)
1000X .5 – 1.3 um